T09 · Insecure Skill Coding Practices
- Location
SKILL.md:243- Finding
Local Username and Hostname Disclosed as a Client Fingerprint
- Content
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Vulnerability Details
File Location:
SKILL.md, lines 243–246
Vulnerability Type: Privacy-sensitive environment information disclosure
Risk Level: MediumComplete Code Snippet:
bash # 在请求头中设置指纹 FINGERPRINT="user-$(whoami)-$(hostname)" # ... curl -s -H "X-Client-Fingerprint: ${FINGERPRINT}" \ "https://aegis402.chain_id=1"Technical Analysis
The Skill instructs the agent to execute
whoamiandhostname, combine the results into a stable client fingerprint, and include that value in an outbound HTTP header. A local username and hostname may reveal a person's identity, organization, device role, internal naming convention, or infrastructure details. They are not required to perform a blockchain address or token risk assessment.The destination shown in the command is malformed and inconsistent with the separately documented
api.example.comdependency. The command will generally fail as written, so the audit does not establish successful disclosure to an operating service. Nevertheless, the documented workflow creates an unsafe disclosure pattern: if the destination resolves in a particular environment or the example is repaired without changing the fingerprint logic, local identifiers will be transmitted externally. A stable value also enables correlation of requests over time.Attack Path
- A user asks the agent to follow the Skill's client-fingerprint example.
- The agent executes
whoamiand obtains the local account name. - The agent executes
hostnameand obtains the device or host name. - Both identifiers are concatenated into
FINGERPRINT. curlplaces the value in theX-Client-Fingerprintrequest header.- If the configured destination resolves and accepts the request, the remote operator receives the local identifiers and can correlate subsequent requests using the stable value.
Impact Assessment
This issue does not grant local code execution, ...[truncated 427 chars]
- Remediation
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Remediation Suggestions
- Remove all use of
whoamiandhostnamewhen constructing request identifiers. - Omit the fingerprint header unless it is strictly necessary for the service.
- If a client identifier is required, generate a random, pseudonymous identifier that contains no environment-derived data. Store it only with informed user consent and provide a way to rotate or delete it.
- Clearly disclose what information is transmitted, why it is required, how long it is retained, and whether it is used for tracking.
- Replace malformed and placeholder destinations with one documented, verified HTTPS API origin.
- Require explicit user confirmation before transmitting any local metadata to an external service.
- Validate the destination against an allowlist and avoid following redirects to untrusted origins.
- Remove all use of
